April 16, 2010

Common PGR Help Creeping Bentgrass Weather Drought

Irrigation water for turfgrass has become increasingly restricted due to environmental factors such as insufficient precipitation; increased domestic, agricultural, and industrial consumption; and contamination of potable water supplies. This water deficit has created an increased need to identify promising water conservation strategies and implement stringent restrictions in water use.

In their ongoing search for ways to improve turfgrass growth in environments where water is limited, scientists are searching for effective water saving practices by looking to factors that influence drought resistance. Discovering which turfgrasses respond favorably to these practices can assist turfgrass management professionals in their selection of water-saving species or cultivars and provide valuable information to the burgeoning turfgrass industry.

A new study examines the effects of the plant growth regulator trinexapac-ethyl (TE) on turf growth and water use for creeping bentgrass (Agrostis stolonifera L.) exposed to drought stress. Researchers from Rutgers University and the Agricultural University of Hebei, China, published the study in a recent issue of the Journal of the American Society for Horticultural Science. According to the study, among the most common practices used for water conservation in turfgrass management is the use of plant growth regulators (PGRs). Trinexapac-ethyl (TE) is one of the most widely used PGRs in the management of turfgrass, used mainly for clipping reduction, seedhead suppression in annual bluegrass, and improvement of overall turf quality.

The researchers sprayed plant foliage of a creeping bentgrass cultivar with TE at 14 days before and at the initiation of drought stress. TE-treated and untreated plants were exposed to well-watered or drought stress conditions for 28 days in a growth chamber. Among the results: TE-treated plants exhibited a reduced rate of water depletion from the soil as demonstrated by higher soil water content, lower evapotranspiration rates, and higher leaf relative water content during 28 days of drought stress compared with non-TE-treated plants.

Bingru Huang, lead researcher of the study, noted that the TE-treated plants maintained significantly higher turf quality and leaf photochemical efficiency under drought stress. Huang noted that "the encouraging effects of TE application on turf growth during drought stress were associated with the reduction in water depletion or lower water use and increases in osmotic adjustment due to the accumulation of inorganic solutes and soluble sugars."

According to the study, similar physiological mechanisms of TE effects on drought performance of turfgrass may be applicable under field conditions. The researchers cautioned that the effectiveness of TE may vary from a controlled environment to field conditions with varying influences of temperatures and light intensities.